1. Technical Field
Embodiments of the invention relate to the field of digital compensation in receivers, and more specifically to compensating I/Q imbalance in receivers.
2. Background Information and Description of Related Art
In digital video broadcast systems, such as those used in terrestrial or satellite transmission (DVB-S and DVB-T), a tuner is used at the end-user site to down-convert the signal in frequency and to provide a first stage of demodulation that yields the baseband quadratures (I and Q components). Due to imperfect analog demodulation, the two quadratures will be off-balance in both phase and amplitude.
This in turn has an adverse effect on the receiver performance in that it causes a distortion of the shape of the QAM/PSK constellation, which results in larger cluster variance and higher bit error rate, and it prevents the proper operation and convergence stability of some of the internal loops of the receiver (for example, the decision directed equalization and phase lock loop).